This article describes an interrupted case study that intersperses information about diffusion and osmosis with content review and knowledge application questions, as well as a simple experiment that can be conducted without the use of a laboratory. The case study was developed for use in an introductory undergraduate biology course. The case…

Provided are procedures for a demonstration which illustrates the concept of summer stratification of lakes in the temperate zone as maintained by thermal resistance to mixing. The demonstration requires only food coloring, water, and common laboratory equipment. (JN)

Describes a laboratory experiment which focuses on the importance of water in germination and seedling emergence. Discusses the activity's design, expected results, and possible application. Offers suggestions for extending the experiment. (ML)

A college level plasmolysis experiment, demonstrating principles of cell/water relations, has been modified to demonstrate the objective collection of data. Background information, laboratory procedures, results, and instructional strategies are provided. (Author/JN)

Describes an inexpensive, reproducible alternative assay that requires minimal preparation and equipment for water testing. It provides students with a direct method of detecting potentially biohazardous material in water by observing the reduction in bacterial luminescence. (PR)